Method of making a frangible seal in a sample processing device

Abstract

A sealing device configured to create a frangible seal in a sample processing device is described. Methods of using the device to create one or more frangible seals in a sample processing device are also described.

The invention claimed is: 
     
       1. A sealing press comprising a pair of isothermally heated dies, the pair including a forward and a reverse die each comprising a sealing surface opposed to each other and adapted to hold therebetween a sample processing device positioned along a sealing plane, wherein the forward and reverse dies are each independently positioned on and controlled by a forward and reverse alignment slider, respectively, the forward and reverse alignment sliders are each mounted to a forward and reverse caliper arm, respectively, and the forward and reverse caliper arms are each mounted to a mechanical linkage connected to an actuator which provides thrust for synchronized movement of the forward and reverse dies, wherein the forward die is connected to an independent forward die control mechanism comprising a forward die driver connected to a supplemental forward die linear slider and an independent forward die controller, wherein the mechanism independently actuates the forward die from the forward caliper arm, thereby adjusting a contact pressure between the sealing surfaces. 
     
     
       2. The sealing press of  claim 1 , wherein the mechanical linkage comprises a lever, a first con rod and a second con rod, wherein the lever comprises a central pivot point and a first and second end, wherein the first con rod is pivotally connected to the first end of the lever and pivotally connected to one end of the reverse caliper arm, wherein the second con rod is pivotally connected to the second end of the lever and pivotally connected to one end of the forward caliper arm, wherein the forward and reverse caliper arms are connected to the forward and reverse alignment sliders, respectively. 
     
     
       3. The sealing press of  claim 1 , wherein the pair of isothermally heated dies are configured to be heated to a constant temperature below a melt temperature of a substrate of the sample processing device. 
     
     
       4. The sealing press of  claim 3  wherein the substrate comprises polypropylene and the dies are heated to about 105-115° C. 
     
     
       5. A method of creating a frangible seal in a sample processing device comprising a hollow tubing substrate having an outer surface and an inner surface, wherein the method is performed by a sealing press comprising a pair of isothermally heated dies, the pair including a forward and a reverse die each comprising a sealing surface opposed to each other and adapted to hold there between a sample processing device positioned along a sealing plane, wherein the forward and reverse dies are each independently positioned on and controlled by a forward and reverse alignment slider, respectively, the forward and reverse alignment sliders are each mounted to a forward and reverse caliper arm, respectively, and the forward and reverse caliper arms are each mounted to a mechanical linkage connected to an actuator which provides thrust for synchronized movement of the forward and reverse dies, wherein the forward die is connected to an independent forward die control mechanism comprising a forward die driver connected to a supplemental forward die linear slider and an independent forward die controller, wherein the mechanism independently actuates the forward die from the forward caliper arm, thereby adjusting a contact pressure between the sealing surfaces, the method comprising:
 (a) maintaining the pair of isothermally heated dies at a constant temperature below a melt temperature of the substrate of the sample processing device; 
 (b) positioning the substrate along the sealing plane of the sealing press; 
 (c) pressing the sealing surfaces of the forward and reverse die into the substrate of the sample processing device at a pressure of approximately 50-100% of a compressive yield strength of the substrate for a time sufficient to transmit heat through an outer surface of the substrate to the inner surfaces of the substrate, thereby forming a partially molten seal; and 
 (d) withdrawing the forward and reverse dies and holding the forward and reverse dies tensionless to allow the partially molten seal to cool and shrink. 
 
     
     
       6. The method of  claim 5 , wherein the pair of isothermally heated dies are maintained at a constant temperature approximately 15-25° C. below the melt temperature of the tubing substrate. 
     
     
       7. The method of  claim 5 , wherein the substrate comprises polypropylene and the pair of isothermally heated dies are maintained at a constant temperature of approximately 105-115° C. 
     
     
       8. The method of  claim 5 , wherein the sealing surfaces of the forward and reverse dies are pressed into the substrate at a pressure of approximately 300-600 psi. 
     
     
       9. The method of  claim 5 , wherein the forward and reverse dies are pressed against the substrate for about 3-6 seconds.